The Catholic Church's Truth, Justice and Healing Council is the church body that will coordinate with the royal commission.

The council's chief Francis Sullivan says the group will cooperate fully.

"This is an opportunity for people who have been damaged, and for other victims of the atrocities, to be given the priority that they need so that a proper process of justice and healing can occur," he told ABC News24.

"This will enable the truth to come out, and you won't get justice and healing without firstly revealing the truth.

"Everybody knows that in the past there has been mismanagement, but the best part about some of this story is that in the present time there have been massive improvements in the whole area around the protocols of child sex abuse."

Mr Sullivan says he is "ashamed" of the way child sex abuse cases have been handled by the church in the past.

"Clearly there were cover-ups and clearly there were situations where the interests of the victims weren't the number one priority," he said.

"At the same time, the Catholic Church provides a massive amount of good in the community ... and it would be a real shame if the slur of child sex abuse hung over the church for years ahead and all the good that occurs is undermined."

But while the royal commission's terms of reference have been welcomed by many, it comes too late for some.

Four decades ago, Jim Boyle's then 14-year-old brother Gavan was sexually abused by a monsignor attached to the Melbourne Cathedral.

Ashamed, Gaven waited until after his parents died to tell his story at age 49, two years before he died.

"He died from a combination of alcoholism, starvation because he neglected himself and cancer that he'd not had treated," Jim Boyle told PM.

"Although it took many, many years, I'd say his death was a direct result of the abuse he suffered."

The commissioners

From top, left to right:

Peter McClellan

Senior NSW Supreme Court judge

Former chair of the Sydney Water Inquiry

Former assistant commissioner at ICAC

Jennifer Coate

New appointee to the Family Court of Australia

Victorian County Court judge and former president of Children's Court

Bob Atkinson

Former Queensland police commissioner

Oversaw police reforms following Fitzgerald inquiry

Andrew Murray

Former WA senator

Advocate on issues surrounding institutionalised children

Helen Milroy

Psychiatrist with a focus on the wellbeing of children

Director for WA's Centre for Aboriginal Medical and Dental Health

Robert Fitzgerald

Commissioner on the Productivity Commission since 2004

Convenes the Indigenous Disadvantage Working Group

Former Community and Disability Services commissioner in NSW

Gavan received some compensation for his abuse, but Mr Boyle says the church badly treated not only his brother but also the family.

He says the inquiry should not overlook that.

"The terms of reference seem to be specific to survivors where sex abuse does occur," he said.

"Both my sister and I have been in shock about it. My wife is terribly traumatised by this process. This damage affects the families involved."

The commissioners, led by New South Wales Supreme Court judge Peter McClellan, will hold a phone hook-up on Monday and meet on Tuesday.

Among the first order of business will be deciding on the structure of the commission.

Ms Gillard says it is a chance for survivors of institutional child sexual abuse to feel Australia is listening.

"To those survivors of child sexual abuse, today we are able to say we want your voices to be heard," she said.

"Even if you've felt for all of your life that no-one's listened to you, that no-one has taken you seriously, that no-one has really cared, the royal commission is an opportunity for your voice to be heard."

Attorney-General Nicola Roxon emphasises the commission's task is to provide advice to government, not to make prosecutions.

"We understand, however, that many of these matters are from a long time ago. Some people have hesitations in going to the police," she said.

"And we do think that the importance of the work of the commission will mean many people will come forward to the commission and may want, and indeed need assistance in referring to the matter to the police.

"So we have asked the commissioners in the terms of reference to consider how they will carefully liaise with police forces across the country."

The details announced today have the Opposition's full support.

"We've examined the terms of reference published by the Government today," shadow attorney-general George Brandis said.

"They seem to us to be very comprehensive and that means that there is no area of child sexual abuse in an institutional context which has been withheld from the purview of the inquiry."

The commissioners have been given until the end of 2015 to deliver their final report.

In an interim report due at the 18-month mark, they will be required to say if they need the commission to go beyond three years.